(1) Field of the Invention
This invention relates to improved brakes.
(2) Description of the Prior Art
Conventional disc brakes comprising opposed actuator plates, steel balls movable in inclined ramps located in adjacent faces of the opposed actuator plates, rotating brake discs and non-rotatable stationary discs operate when a brake pedal connected by a linkage to the actuator plates to rotate relative to each other, which causes the steel balls to roll on the inclined ramps and thus push the actuator plates apart. This results in clamping the two sets of brake discs (i.e. stationary and rotatable) together to give a braking action.
However such conventional disc brakes have been found to be relatively disadvantageous in relation to uneven distribution of load when the stationary brake disc and the rotatable brake disc were clamped together which caused uneven wear on the brake linings. Also conventional disc brakes as described above tend to have the friction linings on the brake discs wearing out rather quickly with a need for consequential replacement.
Also when conventional disc brakes become well used, the steel balls will tend to wear a track in the ramps, and consequently increase the likelihood of the brakes jamming. One solution adopted to overcome this problem was the provision of raised lugs designed as wear bushings. Once the actuator plates were assembled inside a housing the lugs then fitted neatly in the housing. When the actuator plates are turned, the lugs then were designed to constantly assist in keeping the plates in the correct orientation (i.e. "true" or in line). The steel balls were also supposed to assist. However, it was found when the brakes became well used that the lugs were worn down and made a groove in the housing as well as the balls making a track in the ramps. Therefore eventually the friction discs jammed. Also the actuator plates jammed because they never seemed to remain parallel to each other and geometrically at right angles to their rotational plane at the same time. Thus the balls and lugs wore down after use, and the load stress points under rotation were concentrated in too small an area.